The answer comes from trademark law and the aggressive actions taken by the National Football League to protect its rights to the phrase "Super Bowl". For example, in 2015, the league opposed a trademark application for the phrase "Souper Bowl" which was to apply to certain drinkable soups.

Our recommendation to businesses remains the same:The bottom line to remember? Don't imply
that you have any official connection to, endorsement by, or license to
use the National Football League's trademark for "Super Bowl."